Ultra-high sensitive cancerous cells detection and sensing capabilities of photonic biosensor

The ultra-high sensitive cancer cell detection capabilities of one-dimensional photonic crystal with defect have been theoretically examined in this work. The simulations of the work have been carried out with MATLAB programming and transfer matrix method. The performance of the proposed biosensor loaded separately with samples containing different cancer cells has been studied by changing the period number, defect layer thickness, and incident angle corresponding to s polarized light only to identify the parameters under which the proposed design becomes ultra-sensitive. The working principle of the proposed biosensor is to sense the minute change in the refractive index of the analytes containing different cancer cells of human. This sensing is done shifting the respective defect mode inside photonic band gap of the structure from one position to other near by position due to change in the refractive index of sample under consideration. Our structure under optimum conditions yields maximum shifting in the position of defect mode from 1538 to 1648 nm corresponding to the samples containing normal and Glioblastoma cells of refractive indices 1.350 and 1.4470 respectively which results a ultra-high sensitivity of 4270.525928 nm/RIU.

which has life threatening impact on human life.Most of the cancers are in solid form, malignancy may also exist is human in medical science blood cancer disease is known as leukemia 17 .Human body send signals to the normal cells for their development, cancerous cells start developing without getting any signal of their development.Normally deadly cells are extracted or eliminated by our immune system, extraction is not done in the case of cancerous cells 18 .The prevention of malignancy can be only achieved if we could identify the growth of deadly cells in time.The early stage detection of malignancy is only possible if we could have full proof diagnosis mechanism which could provide precise, rapid and cost-effective results.Presently several cancer cell detection techniques are being used in the early stage and timely detection of cancerous cells in human body.Nowadays, microfluidic, plasmonic and photonic biosensing, immunocyte-chemistry and electrochemical technique-based devices are being used for early and timely detection of cancers cells in human body [19][20][21][22] .Recently Chung-Ting et al. presented a sensitive plasmonic biosensing design whose unit cell is composed of closed loop dual band perfect absorber using intersection nanostructure for detection of malignant cells of human body 23 .Moreover, Malek et al. have discussed the high sensitive biosensor composed of 1d defective ternary photonic crystal for early stage detection of cancerous cells of sensitivity 3282.09nm/RIU 24 .
The work of Malek et al. motivated us for this study to design ultra-sensitive biosensor for cancer cell detection.In the current study, the optical properties of the 1d defective ternary photonic crystal (DTPC) have been used for the detection of cancerous cell in human body 24 .We have used in the calculations and simulations the transfer matrix formulation in addition to MATLAB software.Both normal and oblique incidence corresponding to s polarized incident EMWs have been considered in this study.For achieving ultra-high sensitivity from the 1d DTPC while investigating various cancerous cells we have studied the effect of change in period number, incident angle and the thickness of the defect layer on the performance of the design.The organization of the paper is as under."Introduction" section deals with introduction.Structural design and theoretical formulation are presented in "Structural design and its realization" and "Theoretical formulation" sections respectively.Results and discussions are written in "Results and discussions" section.Finally, conclusions are discussed in "Conclusion" section of this manuscript.

Structural design and its realization
The proposed design has been configured by introducing a defect layer D of air at the centre of two ternary photonic crystals such that (ABC) N /D/(ABC) S /Substrate.Here alphabets A, B, and C are being used to represent layers of materials Si, Pbs and SiO 2 respectively.The letters N and S are used to represent period number which is equal in our case.The architecture of the proposed design air/(Si/Pbs/SiO 2 ) N /Defect/(Si/Pbs/SiO 2 ) S /air is shown in

Theoretical formulation
For the simulation of results pertaining to the proposed research work based on TMM, we have used MATLAB programming by using transfer matrix method.The electric and magnetic fields amplitudes at incident media to exit media are connected of through resulting transfer matrix F as 6,[25][26][27] Here F 11 , F 12 , F 21 and F 22 are the elements of matrix F representing whole structure.The 2 by 2 matrix representing individual layers A, B, C and D of DTPCs have been shown by f 1 , f 2 , f 3 and f D respectively.The transmission coefficient representing proposed 1D DTPC air/(Si/Pbs/SiO 2 ) N /Defect/(Si/Pbs/SiO 2 ) S /air can be evaluated with the help of following expression as [28][29][30] where admittance of incident and exit ends of the structure corresponding to s polarized ware are shown by α I = n 0 cosγ 0 and α S = n S cosγ S respectively and for p polarized incident wave, α I = cosγ 0 n 0 and α I = cosγ S n S .The symbols γ 0 and γ S are representing angle of incident and angle of emergence respectively.
Finally, transmittance can be obtained as [30][31][32] The performance of the biosensor based on 1D TPC has been evaluated with the help of one of the most popular parameters named as sensitivity.Actually, while observing the sensitivity of any biosensing structure the ratio of change in the central wavelength of resonant peak ( δ ) due to alteration in the refractive index of the sample ( δn ) under investigation is named as sensitivity of the design.It determines how minutely the biosensor can detect the change in the refractive index of the sample under investigation.It is defined as [33][34][35]

Results and discussions
The refractive indices of different samples containing various cancerous cells of human body examined in this work are presented in Table 2.
In this paper we have examined the change in the position of defect mode due to the corresponding change in the sample poured into cavity region D of the structure.First, we have loaded the proposed design with a sample containing normal cell of human body and simulated the transmission spectra showing a defect mode of unit transmittance positioned at a wavelength 2928.7386nm inside PBG of the structure extending from 2155 to 3800 nm as shown in Fig. 2.
An enlarged view of Fig. 2 has been shown in Fig. 3 below.It is showing the clear picture of defect mode centered at 2928.7386 nm.This figure is very useful for obtaining the numeric values of central wavelength of the defect mode and its full width half maximum as mentioned above.
Next, we have examined the response of the proposed design loaded with samples containing normal, Jurkat, Hela, PC12, MDH-MB231, MCF-7, White matter, Low grade glioma, Glioblastoma cells of human body separately with respect to sample containing normal cells of human body under normal incidence condition.The transmittance response of the proposed biosensor loaded separately with the samples as per the details given in Table 2 is shown in Fig. 4. It has been observed from Fig. 4 that as sample containing cancerous cells Jurkat to Glioblastoma the respective defect modes start shifting towards higher wavelength side inside PBG of the ( Table 2. Refractive index details of samples containing various cells 24 .www.nature.com/scientificreports/structure.This movement of defect mode corresponding to samples of different cells is governed by the condition of standing wave inside laser cavity as discussed in Eq. ( 5) below [28][29][30][31][32][33][34][35] (5) ϕ = s = n eff ρ.Here symbols φ and ρ are being used to show optical and geometrical path differences between the propagating waves inside structure.The notations s, λ and n eff are representing free space wavelength of the light injected into the structure, an integer and effective refractive index of the structure respectively.The increase in the refractive index of the sample poured into the defect layer region D of the structure also increases the n eff which in turn allow the movement of the defect mode inside PBG towards higher wavelength side to keep φ remains same.The movement of all defect modes dependent upon the sample poured into the cavity region D of the structure is measured with respect to the defect mode arises due to sample containing normal cell as shown with black colour in Fig. 4.
The defect mode position shift in the central wavelength of the defect mode position due to change in the refractive index of the sample with respect to the central wavelength of defect mode associated with the sample containing normal cell and the sensitivity of the structure loaded with various samples independently are being summarized in Table 3 below.All these values have been obtained with the help of Fig. 4 in addition to Eq. (5).
It is evident from the data of Table 3 that the sensitivity of proposed structure loaded separately with different samples varies between maximum of 1181.0225 and 1164.146392nm/RIU corresponding to the samples containing Jurkat to Glioblastoma cells respectively under normal incidence.

The effect of the incident angle on the sensitivity
Next, attempts have been further given to improve the sensitivity of the proposed structure loaded independently with samples containing various cancerous cells with respect to normal cell.This purpose has been achieved by increasing the angle of incidence from θ 0 = 0° to θ 0 = 85° in steps of 5° corresponding to s-polarized light only.The defect mode position representing the shift in the central wavelength of the defect mode due to change in the refractive index of the samples with respect to the central wavelength of defect mode associated with the sample containing normal cell and sensitivity of the proposed structure loaded with samples as discussed in Table 2 corresponding to incident angle θ 0 = 5°, 10°, 15°, 20°, 25°, 30°, 35°, 40°, 45°, 50°, 55°, 60°, 65°, 70°, 75°, 80° and 85° under s-polarized wave are given in Tables 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19 and 20 respectively.It has been observed from Tables 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19 and 20 that as incident angle increases from 0° to 85° the performance of the structure also increases as the sensitivity increases.The angle dependent average sensitivity variations of the structure loaded independently with samples are being plotted in Fig. 5 for better understanding.It can be clearly seen from the Fig. 5 that the sensitivity of the proposed designed reaches to maximum when angle of incidence is set to 85°.We have also investigated the impact of change in the angle of incidence on the full width half maximum of resonant peak which in turn affects the performance of the proposed biosensor composed of 1D ternary photonic structure with defect.For this purpose, we have studied the how the positions of left and right edges of defect mode inside photonic band gap of the structure loaded independently with normal sample of refractive index 1.35 corresponding to θ° = 0°, 5°, 10°, 15°, 20°, 25°, 30°, 35°, 40°, 45°, 50°, 55°, 60°, 65°, 70°, 75°, 80° and 85° under s polarized light vary.In fact, this analysis gives us insight while selecting the bests suitable incident angle for our design.Table 22 summarizes the average shifting of left and right edges of defect mode in PBG of the structure loaded independently with all sample dependent upon the incident angle corresponding to s-polarized light.6 that as incident angle increases from 0° to 85° the left and right band edges of defect mode start moving towards lower wavelength side, also their FWHM decreases.Figure 6 below visualize the data presented in above table.It is evident from the Fig. 6 that as incident angle increases from 0° to 85° the FWHM of defect mode starts reducing and becomes lowest at θ 0 = 80°.Further increase in the incident angle results very minute change in the FWHM of the defect mode at θ 0 = 85° it becomes 0.057001243 nm.Thus θ 0 = 85° has been considered as an optimum value of an incident angle corresponding to which our structure becomes sensitive as evident from Table 20.The effect of the cavity layer thickness on the performance at θ 0 = 0°N ext, efforts have further extended to improve the sensitivity of the design.For this purpose, we have fixed incident angle θ 0 = 0° and the samples are being loaded independently into the different structures of cavity thickness d D = 1600 nm, 2400 nm, 3200 nm, 4000 nm, 4800 nm, 5600 nm, 6400 nm, 7200 nm and 8000 nm.The defect mode positions of each structure inside PBG loaded independently with all samples along with the shift in the defect mode positions of the structure with respect to normal sample and the respective sensitivity of the structures with cavity thickness d D = 1D, 2D, 3D, 4D, 5D, 6D, 7D, 8D, and 9D are being summarized in Tables 23, 24, 25, 26, 27, 28, 29, 30 and 31 respectively.23, 24, 25, 26, 27, 28, 29, 30 and 31 that the sensitivity of the structure loaded independently with carcinogenic samples with respect to normal sample increases as cavity layer thickness of the structure increases under normal incidence.The average sensitivity of different structures of cavity layer thickness d D = 800 nm, 1600 nm, 2400 nm, 3200 nm, 4000 nm, 4800 nm, 5600 nm, 6400 nm, 7200 nm and 8000 nm loaded with various samples under investigation at θ 0 = 0° are presented in Table 32 below.The data presented in Table 32 shows as the structure of cavity layer thickness d D = 8000 nm possesses maximum average sensitivity of 1419.107092nm/RIU under normal incidence.The pictorial representation of the data of Table 32 has been shown in Fig. 7.It helps us to estimate the optimum value of the cavity layer thickness for the proposed structure.It shows that the average sensitivity of the thickness initially increases rapidly as the cavity layer thickness up to d D = 2400 nm.Further increase in the cavity layer thickness results moderate enhancement in the average sensitivity of the structure.After d D = 5600 nm the sensitivity increases slowly.The average sensitivity of our design reaches to 1419.107092 nm/RIU which is maximum at θ 0 = 0°.The effect of the period number on the performance at θ 0 = 0°A fter getting the optimized values of incident angle and cavity layer thickness as 85° and 8000 nm respectively, we have focused our attention to get the optimized value of period number for our design to extract best sensing performance of our design.For this purpose, we have chosen cavity layer thickness d D = 800 nm and θ 0 = 0° along with other structural parameters which are identical as discussed above.To get the optimized value of the period number N of the structure we have considered four values of N = S = 3, 4, 5 and 6.The defect mode position inside PBG, shift in the central wavelength and the sensitivity of the structure of cavity thickness d D = 800 nm The average sensitivity of the structures of cavity thickness d D = 800 nm at θ 0 = 0° corresponding to period number N = 3, 4, 5 and 6 from the data presented in Tables 33, 34 and 35 respectively are being shown in Table 36.The pictorial representation of the data presented in Table 36 is shown in Fig. 8.
It is evident form Fig. 8 that the increase in the period number results the drastic fall in the sensitivity of the structure which reaches to minimum when the period number N goes to 6. Thus N = 3 is the optimized value for Table 30.Performance evaluation table showing position of defect mode, shift in the position of defect mode due to change in the refractive index of sample containing various cancerous cells with respect to the sample containing normal cell and the sensitivity of the proposed structure loaded independently with sample containing different cells under normal incidence θ 0 = 0° with cavity thickness d D = 9D = 7200 nm.our design which corresponds to maximum average sensitivity of 1199.179484nm/RIU under normal incidence with d D = 800 nm.Additionally, we have also examined the impact of period number on the average shifting of left and right edges of defect mode for determination the FWHM of our design loaded with all samples independently under normal incidence with cavity of thickness d D = 800 nm.The shift in the left and right edges of defect mode due to change in the period number of the structure is presented in Table 37 below.
The pictorial representation of the data has been shown in the Fig. 9 below.It shows that the average value of the FWHM of the defect mode corresponding to optimum period number 3 is 11.5732787 nm.Any deviation in Figure 7. Plot showing average sensitivity of different structures of cavity layer thickness d D = 800 nm, 1600 nm, 2400 nm, 3200 nm, 4000 nm, 4800 nm, 5600 nm, 6400 nm, 7200 nm and 8000 nm each loaded with various samples under investigation at θ 0 = 0°.the period number from 3 results the deduction in the FWHM value of our design which reaches to minimum at N = 6.

Analysis of the performance of the structure with optimized parameters
After optimizing the incident angle corresponding to s-polarized incident wave, thickness of the cavity region and period number of the structure as 85°, 8000 nm and 3 respectively, we have given our efforts to analyze the performance of the under the influence of optimized external and internal parameters of the proposed structure as θ 0 = 85° and d D = 8000 nm and N = 3 respectively.First, we have designed the defective ternary photonic structure of period number 3 and cavity thickness 8000 nm which is loaded independently with all samples.The s-polarized incident light is allowed pass through the structure at an incident angle 85°.  of Fig. 10.These values have been recorded in Table 38 below.It is evident from the data of Table 38 that as the refractive index of the sample under investigation increases the defect mode position shifted to higher wavelength side in such a way that the shift in the defect mode position associated with sample also increases with respect to the position of defect mode due to sample containing normal cells.Additionally, the sensitivity of the structure under optimized condition varies from maximum of 4325.0875nm/RIU to minimum of 4155.13505nm/RIU corresponding to samples containing Jurkat to Glioblastoma cells respectively.Under optimum conditions the average sensitivity of the proposed structure becomes 4270.525928nm/RIU which is tremendously enhanced.

Analysis of the optimized structure based on other important sensing parameters
This section deals with the analysis of the proposed biosensing structure composed of one-dimensional ternary photonic structure by means of some other important sensing parameters which are very popular and significant in the design and development of plasmonic and photonic biosensors.In addition to sensitivity we have extended the performance evaluation of the proposed structure by calculating numeric values of quality factor (QF), detection limit (DL), sensor resolution (SR), signal-to-noise ratio (SNR), detection range (DR), detection accuracy (DA), figure of merit (FOM) and standard deviation (σ peak ) of our optimized design loaded indepen- dently with sample containing normal and eight carcinogenic cells separately [32][33][34][35][36][37][38][39][40][41][42] .All these calculated values have been listed in Table 39 below.
It has been observed from the data of Table 39 that a FOM value of the proposed sensor varies from 14,711.45719 to 7131.300658 which is high as expected.Additionally, QF and DR values of the proposed structure are also high.The order of the detection limit of the structure is quite low and highlights the minute detection capabilities of our design.The SR, SNR, DA and σ peak values obtained from transmission spectra as shown in Fig. 10 are as per our expectation.These values are supporting our claim of designing ultra-high sensitive biosensor for detection of carcinogenic cells with respect to normal cell.Table 38.Performance evaluation table showing position of defect mode, shift in the position of defect mode due to change in the refractive index of sample containing various cancerous cells with respect to the sample containing normal cell and the sensitivity of the proposed structure with optimized values of cavity thickness d D = 8000 nm and period number N = 3 loaded independently with sample containing different cells at θ 0 = 85° corresponding to s polarized incident light.

Conclusion
In conclusion, we have theoretically examined the biosensing capabilities of 1D defective ternary photonic crystal for accurate and minute identification of cancer cells with respect to normal cell.Both MATLAB computational software and transfer matrix method have been used for obtaining result of this manuscript.The present biosensor works on the principal of refractometric sensing.We have demonstrated how the change in the period number, incident angle corresponding to s-polarized light and thickness of defect layer can be studied to obtain optimized values of these parameters under which our design possesses ultra-high sensitivity.After obtaining optimized values of theses parameters we have calculated QF, DL, SR, SNR, DR, DA, FOM and σ peak values of our structure for analyzing its overall performance.The average sensitivity of 4270.525928nm/RIU can be achieved from our design.FOM, QF and DR values of proposed structure are high whereas DL is low of order 10 -6 .The idea of this manuscript may be very helpful for designing of photonic and plasmonic biosensors.

Fig. 1 .
The refractive indices and thicknesses of layers A, B, C and D of are denoted by n 1 , n 2 , n 3, n d and d 1 , d 2 , d 3 , d d respectively.The refractive indices of the ambient media and substrate of the structure are denoted by n 0 and n s respectively which are air in this case.The numeric values of refractive indices and thicknesses of different layers including semi-infinite media are being presented inTable 1 below.

Figure 1 .
Figure 1.Schematic diagram of a 1d defective ternary photonic crystal with defect.The colours orange, blue, yellow and green are used to show A, B, C and D layers of the structure representing silicon, lead sulphide, silicon di-oxide and defect layer.

Figure 6 .
Figure 6.Angle dependent change in the full width half maximum of defect mode associated with ternary photonic structure loaded independently with all samples.

Figure 8 .
Figure 8. Plot showing average sensitivity of different structures of period number N = 3, 4, 5 and 6 with cavity layer thickness d D = 800 nm under normal incidence.

Figure 9 .
Figure 9. Depiction of period number dependent average shifting of left and right edges of defect mode associated with the structure loaded with all samples independently at θ 0 = 0° and d D = 800 nm.

Table 1 .
Description of refractive indices and thicknesses of different material layers.

Table 4 .
Performance evaluation table showing position of defect mode, shift in the position of defect mode due to change in the refractive index of sample containing various cancerous cells with respect to the sample containing normal cell and the sensitivity of the proposed structure loaded with different cells under normal incidence θ 0 = 5°.

Table 5 .
Performance evaluation table showing position of defect mode, shift in the position of defect mode due to change in the refractive index of sample containing various cancerous cells with respect to the sample containing normal cell and the sensitivity of the proposed structure loaded with different cells under normal incidence θ 0 = 10°.

Table 6 .
Performance evaluation table showing position of defect mode, shift in the position of defect mode due to change in the refractive index of sample containing various cancerous cells with respect to the sample containing normal cell and the sensitivity of the proposed structure loaded with different cells under normal incidence θ 0 = 15°.(C)CellRefractiveindex Defect mode positions (nm) Wavelength shift (nm) Sensitivity (nm/RIU)

Table 7 .
Performance evaluation table showing position of defect mode, shift in the position of defect mode due to change in the refractive index of sample containing various cancerous cells with respect to the sample containing normal cell and the sensitivity of the proposed structure loaded with different cells under normal incidence θ 0 = 20°.

Table 8 .
Performance evaluation table showing position of defect mode, shift in the position of defect mode due to change in the refractive index of sample containing various cancerous cells with respect to the sample containing normal cell and the sensitivity of the proposed structure loaded with different cells under normal incidence θ 0 = 25°.

Table 9 .
Performance evaluation table showing position of defect mode, shift in the position of defect mode due to change in the refractive index of sample containing various cancerous cells with respect to the sample containing normal cell and the sensitivity of the proposed structure loaded with different cells under normal incidence θ 0 = 30°.CellRefractive index Defect mode positions (nm) Wavelength shift (nm) Sensitivity (nm/RIU)

Table 10 .
Performance evaluation table showing position of defect mode, shift in the position of defect mode due to change in the refractive index of sample containing various cancerous cells with respect to the sample containing normal cell and the sensitivity of the proposed structure loaded with different cells under normal incidence θ 0 = 35°.

Table 11 .
Performance evaluation table showing position of defect mode, shift in the position of defect mode due to change in the refractive index of sample containing various cancerous cells with respect to the sample containing normal cell and the sensitivity of the proposed structure loaded with different cells under normal incidence θ 0 = 40°.

Table 12 .
Performance evaluation table showing position of defect mode, shift in the position of defect mode due to change in the refractive index of sample containing various cancerous cells with respect to the sample containing normal cell and the sensitivity of the proposed structure loaded with different cells under normal incidence θ 0 = 45°.

Table 13 .
Performance evaluation table showing position of defect mode, shift in the position of defect mode due to change in the refractive index of sample containing various cancerous cells with respect to the sample containing normal cell and the sensitivity of the proposed structure loaded with different cells under normal incidence θ 0 = 50°.

Table 14 .
Performance evaluation table showing position of defect mode, shift in the position of defect mode due to change in the refractive index of sample containing various cancerous cells with respect to the sample containing normal cell and the sensitivity of the proposed structure loaded with different cells under normal incidence θ 0 = 55°.

Table 15 .
Performance evaluation table showing position of defect mode, shift in the position of defect mode due to change in the refractive index of sample containing various cancerous cells with respect to the sample containing normal cell and the sensitivity of the proposed structure loaded with different cells under normal incidence θ 0 = 60°.

Table 16 .
Performance evaluation table showing position of defect mode, shift in the position of defect mode due to change in the refractive index of sample containing various cancerous cells with respect to the sample containing normal cell and the sensitivity of the proposed structure loaded with different cells under normal incidence θ 0 = 65°.

Table 17 .
Performance evaluation table showing position of defect mode, shift in the position of defect mode due to change in the refractive index of sample containing various cancerous cells with respect to the sample containing normal cell and the sensitivity of the proposed structure loaded with different cells under normal incidence θ 0 = 70°.

Table 18 .
Performance evaluation table showing position of defect mode, shift in the position of defect mode due to change in the refractive index of sample containing various cancerous cells with respect to the sample containing normal cell and the sensitivity of the proposed structure loaded with different cells under normal incidence θ 0 = 75°.

Table 19 .
Performance evaluation table showing position of defect mode, shift in the position of defect mode due to change in the refractive index of sample containing various cancerous cells with respect to the sample containing normal cell and the sensitivity of the proposed structure loaded with different cells under normal incidence θ 0 = 80°.

Table 20 .
Performance evaluation table showing position of defect mode, shift in the position of defect mode due to change in the refractive index of sample containing various cancerous cells with respect to the sample containing normal cell and the sensitivity of the proposed structure loaded with different cells under normal incidence θ 0 = 85°.

Table 21 .
Angle dependent average sensitivity of the proposed design loaded with various samples under investigation.

Table 22 .
An angle dependent average shifting of left and right edges of defect mode associated with the structure loaded independently with all samples.

Table 23 .
Performance evaluation table showing position of defect mode, shift in the position of defect mode due to change in the refractive index of sample containing various cancerous cells with respect to the sample containing normal cell and the sensitivity of the proposed structure loaded independently with sample containing different cells under normal incidence with cavity thickness d D = 2D = 1600 nm.Cell Refractive index Defect mode positions (nm) Wavelength shift (nm) Sensitivity (nm/RIU) Vol.:(0123456789) Scientific Reports | (2023) 13:19524 | https://doi.org/10.1038/s41598-023-46667-ywww.nature.com/scientificreports/

Table 24 .
Performance evaluation table showing position of defect mode, shift in the position of defect mode due to change in the refractive index of sample containing various cancerous cells with respect to the sample containing normal cell and the sensitivity of the proposed structure loaded independently with sample containing different cells under normal incidence θ 0 = 0° with cavity thickness d D = 3D = 2400 nm.

Table 25 .
Performance evaluation table showing position of defect mode, shift in the position of defect mode due to change in the refractive index of sample containing various cancerous cells with respect to the sample containing normal cell and the sensitivity of the proposed structure loaded independently with sample containing different cells under normal incidence θ 0 = 0° with cavity thickness d D = 4D = 3200 nm.

Table 26 .
Performance evaluation table showing position of defect mode, shift in the position of defect mode due to change in the refractive index of sample containing various cancerous cells with respect to the sample containing normal cell and the sensitivity of the proposed structure loaded independently with sample containing different cells under normal incidence θ 0 = 0° with cavity thickness d D = 5D = 4000 nm.

Table 27 .
Performance evaluation table showing position of defect mode, shift in the position of defect mode due to change in the refractive index of sample containing various cancerous cells with respect to the sample containing normal cell and the sensitivity of the proposed structure loaded independently with sample containing different cells under normal incidence θ 0 = 0° with cavity thickness d D = 6D = 4800 nm.

Table 28 .
Performance evaluation table showing position of defect mode, shift in the position of defect mode due to change in the refractive index of sample containing various cancerous cells with respect to the sample containing normal cell and the sensitivity of the proposed structure loaded independently with sample containing different cells under normal incidence θ 0 = 0° with cavity thickness d D = 7D = 5600 nm.

Table 29 .
Performance evaluation table showing position of defect mode, shift in the position of defect mode due to change in the refractive index of sample containing various cancerous cells with respect to the sample containing normal cell and the sensitivity of the proposed structure loaded independently with sample containing different cells under normal incidence θ 0 = 0° with cavity thickness d D = 8D = 6400 nm.θ 0 = 0° loaded independently with all samples with respect to normal sample corresponding to N = 3, 4 and 6 are being given in Tables 33, 34 and 35 respectively.

Table 31 .
Performance evaluation table showing position of defect mode, shift in the position of defect mode due to change in the refractive index of sample containing various cancerous cells with respect to the sample containing normal cell and the sensitivity of the proposed structure loaded independently with sample containing different cells under normal incidence θ 0 = 0° with cavity thickness d D = 10D = 8000 nm.

Table 33 .
Performance evaluation table showing position of defect mode, shift in the position of defect mode due to change in the refractive index of sample containing various cancerous cells with respect to the sample containing normal cell and the sensitivity of the proposed structure with cavity thickness d D = 800 nm and N = 3 loaded independently with sample containing different cells under normal incidence θ 0 = 0°.

Table 34 .
Performance evaluation table showing position of defect mode, shift in the position of defect mode due to change in the refractive index of sample containing various cancerous cells with respect to the sample containing normal cell and the sensitivity of the proposed structure with cavity thickness d D = 800 nm and N = 4 loaded independently with sample containing different cells under normal incidence θ 0 = 0°.

Table 35 .
Performance evaluation table showing position of defect mode, shift in the position of defect mode due to change in the refractive index of sample containing various cancerous cells with respect to the sample containing normal cell and the sensitivity of the proposed structure with cavity thickness d D = 800 nm and N = 6 loaded independently with sample containing different cells under normal incidence θ 0 = 0°.

Table 36 .
Average sensitivity of the proposed design of cavity thickness d D = 800 nm loaded with various samples under investigation at θ 0 = 0° corresponding to period number N = 3, 4, 5 and 6.

Table 37 .
Period number dependent average shifting of left and right edges of defect mode associated with the structure loaded with all samples independently at θ 0 = 0° and d D = 800 nm.

Table 39 .
Performance evaluation table showing numeric values of quality factor (QF), detection limit (DL), sensor resolution (SR), signal-to-noise ratio (SNR), detection range (DR), detection accuracy (DA), figure of merit (FOM) and standard deviation (σ peak ) due to change in the refractive index of sample containing various cancerous cells with respect to the sample containing normal cell of our optimized structure with cavity thickness d D = 8000 nm and period number N = 3 at θ 0 = 85° corresponding to s-polarized incident light.

between the sensitivity of the current work with earlier reported work
Finally, we have compared our findings with the recent work published by various research groups between 2018 and 2021.In this comparison authors have surveyed various biosensing structures based on photonic refractometric technology.The classified information based on the survey has been presented in Table40below.It shows that the proposed structure can be used for designing of ultra-high sensitive biophotonic sensors.This study may provide technological designing insight to the people who are working in the fabrication of biophotonic sensors.